Core with insulation member, and method of producing the same

ABSTRACT

With a stator core ( 20 ) used as ala outer die, a cavity (dA, dB) is formed between the stator core ( 20 ) and a die ( 30 A,  30 B) having a protruding portion ( 31, 32 ) which is inserted in a slot ( 23 ). The cavity (dA) has both side portions (dA 1 ) thereof widen gradually from a slot opening portion toward a depth side. The cavity (dB) widens at a depth side corner portion (dB 2 ). Liquefied resin generally flows evenly through such wide portion into each portion to form a stator core provided with an insulating member. As a result, filling with the synthetic resin can be appropriately conducted while securing a slot space factor and coil insatiability in the core provided with the insulating member formed integrally by synthetic resin.

TECHNICAL FIELD

[0001] The present invention relates to a core provided with an insulating member for insulating a magnet coil in an electric rotating machine (including a motor and a generator) which is constituted by winding the magnet coil around the core of a stator or the like, and a manufacturing method of the same. More specifically, the present invention relates to a core insulating member which is integrally molded by synthetic resin.

BACKGROUND ART

[0002] Generally, an electric rotating machine such as an induction motor and a DC motor (including a generator) is widely used as a power source and the like for industry, vehicle, and other uses.

[0003] In the electric rotating machine, a distributed-winding stator 11, for example, includes a core 12, a coil 13, and a core insulating member 17 as shown in (a) and (b) of FIG. 8. The core 12 includes a yoke 14, a multitude of teeth 15 that protrude from the yoke 14, and a multitude of slots 16 formed between the teeth 15, of which an opening portion is narrower than an inner portion (a depth side). The coil 13 is provided in the slot 16.

[0004] The coil 13 and the core 12 are insulated by the core insulating member 17 made of insulating paper having a U-shaped cross section. The core insulating member 17 is fixed in the slot 16 of the core 12, and interposed between an inner surface of the slot 16 and the coil 13, thereby insulating the inner surface of the slot 16 and the coil 13. Furthermore, the core insulating member 17 has at both ends thereof cuffs 18 that are folded back and protrude in a brim configuration. An end of the cuff 18 is in contact with a side face 12 a of the core 12 that consists of a side face of 15 a of the tooth 15 and a side face 14 a of the yoke 14, and the coil 13 is held above the side face 12 a of the core 12 so as to create a creeping distance 1, thereby securing insulation between the core side face 12 a and the coil 13.

[0005] However, according to such an insulation structure, the folded-back cuff 18 lengthens an axial length of the stator 11 (lateral length in FIG. 8(b)). Therefore, particularly when an electric motor (electric rotating machine) is used as a drive source of a vehicle such as a hybrid vehicle, the axial length of the stator 11 contributes to a vehicle mounting problem. Accordingly, it is preferable that the insulating member is made attachable to the core side face.

[0006] Maximum output of the electric motor for driving a vehicle such as a hybrid vehicle in a limited space is required, and therefore, an increase in the space factor of a magnet wire in the slot is also required. Accordingly, in addition to attaching the insulating member to the core side face, forming (molding) the insulating member by synthetic resin can be considered.

[0007] Conventionally, examples of the core insulating member molded as described above include those disclosed in Japanese Patent Laid-Open Publication No. 2000-78778 and Japanese Patent Laid-Open Publication No. 2000-125524.

[0008] According to Japanese Patent Laid-Open Publication No. 2000-78778 (the former), the yoke and the teeth are constituted separately. After the teeth are fitted with coils, the teeth with fitted coils are attached to the yoke. Then, with this assembly framed by a core and a base plate, liquid resin molding material is poured or injected between the coil and the teeth, so that all teeth with fitted coils and the yoke are fixed and intergrated by electric insulating resin. In this case, a groove portion is formed in a longitudinal direction on both peripheral side faces of the coil-fitted portion of the teeth, and resin is appropriately poured between the coil and the teeth through the groove portion.

[0009] According to Japanese Patent Laid-Open Publication No. 2000-125524 (the latter), an insulating layer covering die is formed by a stator core (stator) in which a multitude of silicon steel plates are laminated, a core die block with an outer shape to be inserted into a slot of the stator core, a movable die block, a positioning die block, and a fixed die block. Resin is injected into the insulating layer covering die to integrally mold a resin insulating layer. In this case, a die block supporting portion corresponding to the center of the teeth of the stator core is provided, and the stator core is supported by the supporting portion so as to secure a uniform clearance between the die block and an end face of the stator core. Accordingly, the thickness of the resin is made uniform and a non-resin filled portion is eliminated so that the thickness of the insulating layer can be made thin.

[0010] According to the former art described above, coils are fitted to the teeth in a state separate from the yoke, and the insulating resin is poured between the coils, the teeth, and the yoke with the teeth with fitted coils attached to the yoke. This is not applicable to a structure in which a core insulating member is fitted in advance to a core that has the teeth and the yoke integrally formed, with the coil then wound around the core. In addition, it is difficult to integrally mold the insulating member on the core end face. Furthermore, the groove portion for securing the flow of resin is formed on both peripheral side faces of the tooth, but the groove portion reduces the cross-sectional area of the tooth which is a magnetic flux path, thereby possibly lowering efficiency.

[0011] Meanwhile, according to the latter art, with the stator core (stator) being used as a part of the die, a thin insulating layer having a uniform thickness is formed by resin molding on the core end face and the slot peripheral face of the stator core. However, particularly in the electric motor which serves as a drive source of a vehicle such as a hybrid vehicle, the diameter of the core (stator) becomes large. Thus, due to this and the aforementioned thin insulating layer having a uniform thickness, it becomes difficult to appropriately fill an entire length of the core with resin.

[0012] Therefore, it is an object of the present invention to provide a core provided with an insulating member that is formed by pouring synthetic resin and a manufacturing method of the same, wherein the synthetic resin can be poured appropriately while a slot space factor and coil insatiability are secured.

DISCLOSURE OF THE INVENTION

[0013] According to claim 1 of the present invention, a core provided with an insulating member comprises a core (20) having a multitude of slots (23) formed between a multitude of teeth (22) that protrude from the yoke (21), and an insulating member (25) having a slot portion (25 a) covering the slot and a core end face portion (25 b) covering a core end face (20 a). The core provided with the insulating member is characterized in that the slot (23) has a side face (23 b) and a bottom face (23 c) formed in a generally flat shape, a core side face (c) of the slot portion (25 a) of the insulating member is formed in contact with the side face (23 b) and the bottom face (23 c) of the slot, a coil side face (w) of the slot portion (25 a) of the insulating member has both side portions (25 a 1) and a bottom face (25 a 2) formed in a generally flat shape, and the slot portion (25 a) of the insulating member has a thick portion (b2, b3, b4) in at least one portion that is thicker than other portions.

[0014] According to claim 1 of the present invention, the slot portion of the insulating member has a core side face thereof that runs along a generally linear shape of the core slot, and therefore a magnetic flux path with a large cross-sectional area can be secured without forming a notch and the like on the teeth. Furthermore, the coil side face of the slot portion is also formed in a generally flat shape, and a sufficient slot space factor and coil insatiability can be secured. In addition, since the slot portion is provided with a thick portion in at least one portion, a flow path of insulating resin material during molding can be secured, and the resin material fills accurately and securely, thus allowing the insulating member to be formed in an accurate and thin shape. As a result, a space that is occupied by the insulating member can be decreased, thereby reducing the size of an electric rotating machine using the core, and also allowing improvement of reliability with respect to insulation.

[0015] In this case, the core may be a stator core or a rotor core, and also includes teeth extending in an outer radial direction as well as in an inner radial direction. Furthermore, the generally flat shape with regard to the slot of the core and the slot portion of the insulating member naturally includes a flat surface formed by a straight line, in addition to including a curve such as an arc or oval with a large curvature radius. In short, the generally flat shape includes shapes that form a substantially straight line connected by a smooth line with no sharp angles.

[0016] According to claim 2 of the present invention, the core provided with the insulating member according to claim 1 is such that the insulating member (25) is made of integrally formed synthetic resin, and fitted integrally to the core (20).

[0017] According to claim 2 of the present invention, the insulating member can be applied to the core in which the teeth and the yoke are integrally formed.

[0018] According to claim 3 of the present invention, the core provided with the insulating member according to claim 1 is such that the core (20) is a stator core (20) which has a multitude of slots (23), a depth side of which is wider than an opening portion (23 a) side, formed between the multitude of teeth (22) protruding from the yoke (21) in an inner radial direction.

[0019] According to claim 3 of the present invention, since the teeth protrude in the inner radial direction of the yoke, and the depth side of the slot is formed wider than the opening portion side by forming the thick portion at the depth side of the slot, the effect of the thick portion on the slot space factor and the coil insertability can be suppressed.

[0020] According to claim 4 of the present invention (for example, refer to FIG. 3(a) and FIG. 5(a)), the core provided with the insulating member according to claim 1 is such that the slot portion (25A, 25A′) of the insulating member is formed so that a thickness of both side portions (25 a 1) gradually increases (b1→b2) from the opening portion (23 a) side toward the depth side of the slot.

[0021] According to claim 4 of the present invention, since the thickness of both side portions of the slot portion of the insulating member is increased gradually from the opening portion side toward the depth side, the thick portion of a predetermined range can be secured with little effect on the slot space factor and the coil insertability. Consequently, flowability of the insulating resin can be secured and uniformity of the flow can be improved, thereby enabling prevention of resin filling defects particularly at the core end face that is in contact with the yoke.

[0022] According to claim 5 of the present invention (for example, refer to FIG. 3 (a)), the core provided with the insulating member according to claim 4 is such that the slot portion (25A) of the insulating member has a bottom portion (25 a 2) formed generally the same thickness (b3) as a thickness (b2) of the depth side of both side portions.

[0023] According to claim 5 of the present invention, since the bottom portion is also formed with the thick portion, a flow path of insulating resin can be secured, and resin filling defects at the core end face portion can be prevented.

[0024] According to claim 6 of the present invention (for example, refer to FIG. 5(a)), the core provided with the insulating member according to claim 4 is such that the slot portion (25A′) of the insulating member has a bottom portion (25 a 2) formed of a thickness (b5) that is thinner than the thickness (b2) of the depth side of both side portions.

[0025] According to claim 6 of the present invention, the speed of flow of resin from the bottom side of the slot portion constituting the thick portion, to the bottom portion and the opening portion side of the slot portion is made uniform, thus enabling prevention of inadequate filling of resin in the slot portion.

[0026] According to claim 7 of the present invention (for example, refer to FIG. 3(b)), the core provided with the insulating member according to claim 1 is such that the slot portion (25B) of the insulating member comprises a thick portion (b4) in which a depth side corner portion (25 a 3) of the slot has been cut off.

[0027] According to claim 7 of the present invention, since the depth side corner portion of the slot portion of the insulating member is formed with the thick portion with cut-off corners, a thick portion having a relatively large thickness can be located at a position where there is little effect on the slot space factor and coil insertability, and flowability and uniformity of the insulating resin can be secured. Consequently, an accurate and thin insulating member can be molded, and resin filling defects particularly at the core end face portion that is in contact with the yoke can be prevented.

[0028] According to claim 8 of the present invention, the core provided with the insulating member according to claim 1 is such that the slot portion (25 a) of the insulating member includes the thick portion (b2, b3, b4) continuing from one core end face (20 a) to the other core end face (20 a).

[0029] According to claim 8 of the present invention, since the thick portion continues from one core end face to the other core end face, the flow path of the insulating resin material during molding call be secured, and the insulating member, particularly the core end face portion, can be formed accurately and securely.

[0030] According to claim 9 of the present invention (for example, refer to FIG. 6(a) and (d)), the core provided with the insulating member according to claim 1 is such that a ridge portion (g) between the tooth and the core end face of the insulating member (25) forms a corner portion (R, 25R) with a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center.

[0031] According to claim 9 of the present invention, since the insulating member corresponding to the ridge portion between the tooth and the core end face is formed by the corner portion with the chamfer shape or the rounded shape with a large curvature radius, a path for filling the core end face portion with the insulating resin can be secured. In addition, a magnet wire of a portion in contact with the ridge is protected by the corner portion, thus allowing the improvement of reliability of the electric rotating machine.

[0032] According to claim 10 of the present invention (for example, refer to FIG. 6(d)), the core provided with the insulating member according to claim 9 is such that the core end face portion of the insulating member is formed in a recessed shape (37) so that a center portion in a width direction of the tooth is thinner than the corner portion (25R).

[0033] According to claim 10 of the present invention, the center portion of the core end face portion in the width direction of the tooth is not necessary for coil protection and the insulating resin path as explained above, and therefore, this center portion can be recessed to achieve a reduction in the amount of the insulating material used.

[0034] According to claim 11 of the present invention (for example, refer to FIG. 4 and FIG. 5(b)), a method of manufacturing a core provided with an insulating member is such that, a cavity is formed, using the core (20) as a die, between the core and a die (30A, 30B) having a protruding portion (31, 32) which is inserted in the slot, the cavity having at least one portion (dA2, dB2, dC3) thereof with a clearance wider than other portions (dA1, dB1, dC1, dC2), and liquefied insulating resin material (25′) is poured in the cavity. As a result, synthetic resin filling the cavity forms the insulating member such that a core side face (c) of the slot portion (25 a) has both side faces and a bottom face formed in a generally flat shape, a coil side face (w) has both side faces (25 a 1) and a bottom face (25 a 2) formed in a generally flat shape, and the slot portion has a thick portion (b2, b3, b4) in at least one portion that is thicker than other portions.

[0035] According to claim 11 of the present invention, since, the insulating member is integrally molded, using the core as the die, between the core and the die having the protruding portion which is inserted in the slot, by the cavity having at least one portion thereof with a clearance wider than other portions, the resin path within the cavity is secured, and the resin is poured substantially uniformly and securely into each portion. Thus, the core provided with a relatively thin insulating member can be molded accurately and securely with the use of a simple device.

[0036] According to claim 12 of the present invention (for example, refer to FIG. 6 and FIG. 7), the method of manufacturing the core provided with the insulating member according to claim 11 is characterized in that a cavity is formed, using the core (20) as the die, between the core and a die with a recessed portion in which a portion corresponding to the ridge (g) between the tooth (22) and the core end face (20 a) is wide, the cavity is filled with liquefied insulating resin material to form a thick portion (35, 36) on a core end face portion corresponding to the recessed portion, and the thick portion is heated and pressed such that the ridge (g) portion forms a corner portion (25R) of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center.

[0037] According to claim 12 of the present invention, since the portion of the cavity that corresponds to the ridge portion between the tooth and the core end face is made wide to secure the flow of resin to the core end face portion of the teeth portion, and the thick portion at the ridge portion thus obtained is heated and pressed to mold the corner portion, the core end face portion of the insulating member having the corner portion can be molded securely and accurately.

[0038] According to claim 13 of the present invention, the method of manufacturing the core provided with the insulating member according to claim 11 is characterized in that a cavity is formed, using the core (20) as the die, between the core and a die opposing the core end face, by the ridge portion (g) between the tooth (22) and the core end face (20 a) so as to correspond to a corner portion (R) of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center, and the cavity is filled with liquefied insulating resin material to mold the corner portion (R).

[0039] According to claim 13 of the present invention, since the corner portion is directly molded by the die, an additional process such as hot forming is not required.

[0040] According to claim 14 of the present invention, the method of manufacturing the core provided with the insulating member according to claim 11 is characterized in that, a first cavity is formed, using the core (20) as a die, between the core and a die opposing one core end face (20 a), wherein the first cavity has a recessed portion in which a portion corresponding to the ridge (g) between the tooth (22) and the core end face (20 a) is wide; a second cavity is formed by the ridge portion (g) between the tooth (22) and the core end face (20 a) between the core (20) and a die opposing the other core end face (20 a), and corresponds to a corner portion (R) of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center; the liquefied insulating resin material fills the first cavity to form a thick portion (35, 36) at a core end face portion corresponding to the recessed portion; the thick portion is heated and pressed to mold the corner portion (25R) at the one core end face; and the liquefied insulating resin material fills the second cavity to form the corner portion (R) at the other core end face.

[0041] According to claim 14 of the present invention, the corner portion of one core end face is molded by the method according to claim 12, and the other core end face is directly molded by the die according to claim 13 without complicating the die division, while securing the flow of resin into the core end face portion. Therefore, an additional process such as hot forming can be reduced by half.

[0042] It should be noted that, the aforementioned reference numerals in parentheses are for reference to the drawings, and are used for convenience to facilitate correspondence between each element of the present invention and the drawings showing the embodiments as well as accelerate understanding of the present invention, thus having no effect on the scope of the structure described in the claims of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]FIG. 1 is a drawing illustrating an entire stator core provided with an insulating member, in which (a) is a center cross sectional view and (b) is a front elevational view;

[0044]FIG. 2 is an enlarged view illustrating a part of the stator core provided with the insulating member, in which (a) is a cross sectional view and (b) is a front elevational view;

[0045]FIG. 3 is a front elevational view illustrating a slot portion of the insulating member, in which (a) and (b) respectively show different embodiments;

[0046]FIG. 4 is a drawing illustrating a manufacturing method of the stator core provided with the insulating member, in which (a) and (b) respectively show different embodiments;

[0047]FIG. 5 is a drawing illustrating the slot portion of the insulating member which is partially modified, in which (a) is a front elevational view and (b) is a drawing illustrating a manufacturing method of the same;

[0048]FIG. 6 is a drawing illustrating a ridge portion between a tooth and a core end portion, in which (a) is a perspective view and (b) is an end face view taken along a line X-X in FIG. 2;

[0049]FIG. 7 is a drawing illustrating an end face taken along the line X-X in FIG. 2 (a), in which (a) shows a corner portion of the insulating member at a ridge portion between the tooth and the core end face, (b) and (c) respectively show different embodiments illustrating die molding and the corner portion, and (d) shows the corner portion according to a different embodiment; and

[0050]FIG. 8 is a drawing illustrating an insulating member and a part of a core according to a conventional art, in which (a) is a front elevational view and (b) is a cross sectional view.

BEST MODE FOR CARRYING OUT TI-I E INVENTION

[0051] Embodiments according to the present invention will be described hereinafter with reference to the accompanying, drawings. FIG. 1 is a drawing illustrating an entire stator core fitted with an electric insulating member according to the present invention, and FIG. 2 is an enlarged view illustrating a part of such a stator core. The stator is preferably used, for example, in a motor generator of a driving system of a hybrid vehicle disclosed in Japanese Patent Laid-Open Publication No. 2001-163071. However, the application of the stator is not limited to this, and the stator may be used, for example, in a generator or motor of a drive system of a hybrid vehicle disclosed in Japanese Patent Laid-Open Publication No. 2001-187535, and is further applicable to electric rotating machines other than transportation machines.

[0052] The aforementioned stator core 20 has, in an integral form, an annular yoke 21 and a multitude of teeth 22 that protrude from the yoke in an inner radial direction at regular intervals. Between the multitude of teeth, a multitude of slots 23, an opening portion 23 a of which is narrower than an inner portion (a depth side), are formed. The tooth 22 extends in such a manner that a center line in a width direction thereof is directed toward a center point of the stator core 20, and both sides of the tooth 22 extend in parallel with the center line. Therefore, the teeth 22 have a uniform width, and the slots 23 widen in a width direction from the opening portion (entrance) 23 a toward the depth side.

[0053] Both side faces 23 b, 23 b and a bottom face 23 c of the slot 23 and both end faces 20 a, 20 a of the core are fitted with an electrical insulating member 25 that is integrally molded. Namely, the insulating member 25 is integrally molded by electric insulating synthetic resin and has a slot portion 25 a connected with the slot 23 portion and a side face portion 25 b connected with the core end face 20 a portion, that is, the side end face of the tooth 22 and the inner diameter portion of the side end face of the yoke 21. More specifically, as shown in FIG. 2, the slot portion 25 a of the insulating member is formed of a length such that a portion 22 a of the tooth 22 at the opening 23 a is exposed, and the end face portion 25 a is also formed of a length such that a portion of a peripheral portion 21 a of the yoke is exposed.

[0054] Furthermore, the slot portion 25 a of the insulating member is formed such that a core side face c thereof is formed along the stator core 20 that constitutes the slot 23, a coil side face w is thick at least in one portion thereof, and the thickness with the inner side face w changes smoothly. That is, the core side face c runs along both side faces 23 b and the bottom face 23 c of the slot 23, which are formed from a linear shape, and the coil side face w consists of both side portions 25 a 1 and the bottom portion 25 a 2 formed from the linear shape.

[0055] More specifically, as shown in FIG. 3(a), the slot portion 25 a of an insulating member 25A is such that the thickness of both side portions 25 a 1 gradually increases from the opening portion 23 a toward the depth side portion (the bottom face 23 c portion). That is, the thickness of both side portions 25 a 1 is thinnest at an opening portion b1 (e.g. 0.25 [m]) and thickest at a depth side portion b2 (e.g. 0.5 [mm]), and the thickness changes linearly therebetween (asymptotic change). In addition, the bottom face portion 25 a 2 is formed of a thickness b3 generally the same (b2) as the depth side portion b2.

[0056] According to another example, as shown in FIG. 3(b), the slot portion 25 a of an insulating member 25B is such that both side faces 25 a 1 are formed with a thin thickness b1, and corner portions 25 a 3 on the depth side are obliquely cut from both side portions 25 a 1 to the bottom face portion on 25 a 2 so as to obtain a thickness b4. Accordingly, in both (a) and (b) of FIG. 3, the teeth 22 have a width similar to conventional cases and can secure a sufficient magnetic flux path. The slot portion 25 a of the insulating member has at least ill one portion thereof the thick portions b2, b3, and b4, and secures a flow path of insulating member material consisting of synthetic resin.

[0057] Furthermore, a coil (13; refer to FIG. 6) is inserted in the slot 23. According to the embodiment shown in FIG. 3(a), even though the thickness of both side portions 25 a 1 of the insulating member 25 increases gradually toward the depth side due to the depth side of the slot 23 being icier than the entrance side, the depth side of the slot 23 is not narrowed thereby, and thus no hindrance to insertion of the coil into the slot 23 is created. Also, according, to the embodiment in FIG. 3(b), since the depth side of the slot 23 is wider as mentioned above, the depth side corner portions of the slot 23 tend to create a clearance with the coil. Therefore, even though the depth side corner portions 25 a 3 of the insulating member are thick, there is no hindrance to insertion of the coil into the slot 23.

[0058] Next, a manufacturing and fitting method of the insulating member 25 will be explained with reference to FIG. 4. As in Japanese Patent Laid-Open Publication No. 2000-125524, the stator core 20 is set within a die so that the core itself constitutes a part of the die. A cavity d ( . . . ) for the slot portion 25 a is formed between the stator core 20 serving as an outer die of the die, and inner dies 30A, 30B. Further, a cavity for the end face portion 25 b is formed by setting an upper die and a lower die on top and bottom faces of the stator core 20. In this case, a positioning shaft or frame is provided so as to prevent displacement of each die.

[0059]FIG. 4(a) is a drawing illustrating a manufacturing method of the insulating member 25A shown in FIG. 3(a). Using the stator core as an outer die, a predetermined cavity dA (1, 2) is formed between the core and the inner die 30A. The inner die 30A has a protruding portion 31 which is inserted in the slot 23 of the core 20, and the protruding portion 31 is formed such that a clearance with both side faces 23 a of the slot 23 is increased gradually from an entrance portion (opening portion side) toward the depth side. Therefore, the cavity dA1, which is formed between both side portions 23 b of the slot 23 and both side faces 31a of the protruding portion of the inner die, widens gradually from the entrance portion toward the depth side, and the cavity dA2, which is formed between the bottom portion 23 c of the slot and a protruding portion end 31b of the inner die, consists of a clearance generally the same as the widest clearance mentioned above.

[0060] On the other hand, FIG. 4(b) is a drawing which illustrates a manufacturing method of the insulating member 25B shown in FIG. 3(b). With the same stator core 20 used as an outer die, a predetermined cavity dB (1, 2) is formed between the core and the inner die 30B. The inner die 30B his u protruding portion 32 which is inserted in the slot 23 of the core 20. The protruding portion 32 has an end corner portion 32 b obliquely cut such that a clearance with both side portions 23 a of the slot 23 is relatively narrow and generally uniform, and a clearance with a depth side corner portion 23 d of the slot 23 becomes wide. Accordingly, the cavity dB1, which is formed between both side portions 23 a of the slot and both side faces 32 a of the protruding portion of the inner die, consists of a generally uniform clearance which is relatively narrow, and the cavity dB2 formed between the bottom portion 23 c of the slot and the end corner portion 32 b of the inner die protruding portion consists of a wide clearance.

[0061] In a state where the stator core 20 and each die including the inner die 30A or 30B are set (die clamped state), by using an injection molding machine or according to another method, insulating resin material is heated and plasticized, and liquefied resin material 25′ is injected into the cavity dA or dB. In this case, the cavity dA or dB consists of a wide clearance portion (the depth side portion and the bottom portion dA2 or the depth side corner portion dB2), and the resin material passes through the wide clearance portion, securely flows into a narrow clearance portion (the slot entrance portion dA1 or both side portions dB1) of both side portions of the slot and into a cavity between the lower die (or the upper die) and the core end face portion 25 b. As a result, the resin accurately fills the cavity for the slot portion and the cavity for the core end face. That is, the liquefied resin passes through the wide cavity portions dA2 and dB2, and flows in a vertical direction and into the narrow portions dA1 and dB2 to securely fill the slot portion 25 a. Also, it flows into the cavity between the core end face and the lower die (and the upper die). In this case, the cavity for the core end face consists of a wide clearance similar to the aforementioned wide portion. The resin also flows into an inner diameter annular portion of the end face of the yoke 21 and the end face portion of the tooth 22 to fill the core end face portion 25 b. Accordingly, uniformity of the resin flow is secured, and resin can be poured securely and accurately into each portion of the insulating member without generating filling defects.

[0062] Then, in a state where the resin material is cooled and solidified, each die set as described above is separated (die release), and the inner dies 30A, 30B and the upper die, the lower die and the like are separated from the stator core 20. Accordingly, the insulating resin 25′ filling the cavities dA, dB becomes the insulating member 25 (25A, 25B) shown in FIG. 1, FIG. 2, (a) or (b) of FIG. 3, and the like, which is fitted to the stator core 20. As a result, the stator core provided with the insulating member is formed.

[0063]FIG. 5(a) is a drawing illustrating the embodiment in FIG. 3(a) with partial modification. As in FIG. 3(a), the thickness of both side portions 25 a 1 of the slot portion 25 a of an insulating member 25A′ increases gradually from the opening portion 23 a toward the depth side portion (the bottom face 23 c side). The bottom portion 25 a 2 of the slot portion 25 a is different from that of FIG. 3(a) in that a thickness b5 of the bottom portion 25 a 2 is generally the same as the thickness b1 of the opening portion 23 a of both side portions 25 a 1 (b5≈b1), that is, the thinnest thickness (e.g. 0.25 [m]) of the side portion with a gradually increasing thickness. In this case, the thickness b5 of the bottom portion 25 a 2 need not necessarily be b5 b1 as mentioned above, and the thickness b5 as less than the thickest thickness b2 at the depth side of both side portions 25 a 1 (b5<b2) will suffice.

[0064]FIG. 5(b) is a drawing illustrating a manufacturing method of the insulating member 25A′. With the stator core used as an outer die, a predetermined cavity dC (1, 2) is formed between the core and an inner die 30C. Cavities dC1, dC3 defined by both side faces 33 a of a protruding portion 3) of the inner die 30C inserted in the slot 23 of the core 20 are formed, as in the case with FIG. 4(a), such that a clearance with both side faces 23 b of the slot 23 widens gradually from the entrance portion (opening portion side) toward the depth side. However., this embodiment differs from the aforementioned embodiment in that the cavity dC2 between an end 33 b of the protruding portion 33 and the bottom face 23 c of the slot of the core consists of a clearance generally the same as the clearance at the entrance portion. Accordingly, the cavities dC1, dC3 that form the slot portion 25 a 1 widen gradually from the entrance portion toward the depth side, and the cavity dC3 at the depth side forms the thick portion. In addition, the cavity dC2 that forms the bottom portion 25 a 2 consists of a relatively narrow clearance that is generally the same as the width of the cavity dC1 at the entrance portion.

[0065] According to the embodiment described earlier shown in FIG. 4(a), since the cavity dA2 at the bottom portion is wide, the flow speed of resin that flows through the cavity on the depth side and bottom portion of the slot becomes excessively fast depending on the type of resin material forming the insulating member, thereby filling such a cavity first, which possibly leads to inadequate filling of resin on the entrance side of the slot portion. However, according to the present embodiment, since the cavity dC2 at the bottom portion is relatively narrow, the flow speed of resin that flows into the entrance side and the bottom portion through the wide cavity dC3 at the depth side of the slot portion is uniformed, thus eliminating the possibility of inadequate filling of resin on the entrance side of the slot portion.

[0066]FIG. 6 is a drawing illustrating a part of the core end face portion 25 b of the insulating member. As shown in FIG. 6(a) a yoke 21 portion 25 b 1 of the core end face portion 25 b extends in an annular shape and the end face portion 25 b itself is formed thick. Also, resin quickly flows into the yoke portion 25 b 1 through the wide cavity portions dA2, dB2, and dC3 as described above, so that the resin flows generally evenly into the yoke portion 25 b 1 and the tooth 22 portion 25 b 2. Furthermore, as shown in FIG. 5(b), if a coiner portion R on a ridge g portion between the tooth 21 and the core end face 20 a is formed with uniform thickness, the corner portion R of the insulating member becomes thin, which may causes defective insulation when inserting a magnet wire into the slot and the like.

[0067]FIG. 7, identical to FIG. 6, is a cross-sectional view of the teeth 22 portion taken along a line X-X in FIG. 2. As shown in FIG. 7(a), the insulating member 25 on the ridge portion g between the tooth 22 and the core end face 20 a is provided with a corner portion 25R of a chamfer shape or a rounded shape having a curvature radius larger than the thickness of the insulating member 25 by offsetting the center of curvature from the ridge toward a tooth inward direction. The insulating member 25 b of the core end face portion is connected to the insulating member 25 a of the slot portion through the corner portion 25R, and is formed a predetermined thickness greater than the slot portion. Consequently, a magnet wire when inserted into the slots 23 sandwiching the teeth 22, or a connecting portion of the slot portion and the coil end portion of the magnet wire, comes into contact with the large-radius corner portion 25R, thereby enabling protection of the magnet wire.

[0068] The corner portion 25R may be molded by upper and lower dies that are designed to correspond to the corner portion when molding the insulating member by injection molding or the like as described above. However, it is preferable to perform molding as follows in order to simplify the die structure. A part of the upper and lower dies that corresponds to the ridge portion g between the tooth 22 and the core end face 20 a is formed in a stepped flat shape or a recessed shape having a trapezoidal cross section. Accordingly, when the insulting member is molded by injection molding or the like using the die, the insulating, member corner portion 25R is molded so as to protrude in a rectangular cross-sectional shape 35 as shown in FIG. 7(b) or a triangular cross-sectional shape 36 as shown in FIG. 7(c). In this state, a heated roller or die is pressed against the thick portion of the protruding rectangular cross-sectional shape or triangular cross-sectional shape, such that the corner portion 25R is molded in a chamfer shape or a rounded shape having a large curvature radius as explained above.

[0069] As a result, the resin material can securely fill the core end face portion 25 b from the rectangular or triangular cross-sectional shape portions 35, 36 having a wide cross-sectional area during the flow of insulating resin material by injection molding or the like, as well as due to the wide cavities dA2, dB2, and dC3 of the slot portion. Furthermore, when the cross-sectional area of the protruding cross-sectional shapes 35, 36 is large, the core end face portion 25 b is formed with uniform thickness continuing from the corner portion 25R as shown in FIG. 7(a). When the cross-sectional area is small, the core end face 25 b of the insulating member is formed in a shape where the center part of the tooth 22 is recessed as shown in FIG. 7(d). A recessed portion 37 allows a reduction in the amount of the insulating resin material used, without impairing the magnet wire protection function of the corner portion 25R mentioned above.

[0070] Furthermore, a corner portion of one core end face 20 a may be molded in a heating and pressurizing process using the heated roller or the like as described earlier, while a corner portion of the other core end face may be molded by directly filling the cavity formed in the upper die with resin.

INDUSTRIAL APPLICATION

[0071] The stator core provided with the insulating member according to the present invention can be used in a motor and a generator used as a power source in all fields including industrial and transportation use and is suitable for use in an electric rotating machine (motor generator) for a vehicle with a limited mounting space, and in particular, for a hybrid vehicle. 

1. A core provided with an insulating member, comprising a core having a multitude of slots formed between a multitude of teeth protruding from a yoke, and an insulating member having a slot portion covering the slot and a core end face portion covering an end face of the core, characterized in that the slot has a side face and a bottom face that are formed in a generally flat shape, a core side face of the slot portion of the insulating member is formed in contact with the side face and the bottom face of the slot, and the coil side face of the slot portion of the insulating member has both side portions and a bottom face that are formed in a generally flat shape, and the slot portion of the insulating member has a thick portion in at least one portion that is thicker than other portions.
 2. The core provided with the insulating member according to claim 1, wherein the insulating member is made of integrally formed synthetic resin and is integrally fitted to the core.
 3. The core provided with the insulating member according to claim 1, wherein the core is a stator core which has a multitude of slots, a depth side of which is wider than an opening portion side, formed between the multitude of teeth protruding from the yoke in an inner radial direction.
 4. The core provided with the insulating member according to claim 1, wherein the slot portion of the insulating member is formed such that a thickness of both side portions gradually increases from the opening portion side toward the depth side of the slot.
 5. The core provided with the insulating member according to claim 4, wherein the slot portion of the insulating member is such that the bottom portion is generally the same thickness as a thickness of the depth side of both side portions.
 6. The core provided with the insulating member according to claim 4, wherein the slot portion of the insulating member is such that the bottom portion is thinner than a thickness of the depth side of both side portions.
 7. The core provided with the insulating member according to claim 1, wherein the slot portion of the insulating member comprises a thick portion in which a depth side corner portion of the slot has been cut off.
 8. The core provided with the insulating member according to claim 1, wherein the slot portion of the insulating member is such that the thick portion continues from one core end face to the other core end face.
 9. The core provided with the insulating member according to claim 1, wherein a ridge portion between the tooth and the core end face of the insulating member forms a corner portion with a chamber shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center.
 10. The core provided with the insulting, member according to claim 9, wherein the core end face portion of the insulating member is formed in a recessed shape such that a center portion in a width direction of the tooth is thinner than the corner portion.
 11. A method of manufacturing a core provided with an insulating member, by forming a cavity, using the core as a die, between the core and a die having a protruding portion which is inserted in a slot the cavity having at least one portion thereof with a clearance wider than other portions, and pouring liquefied insulating resin material in the cavity, wherein the insulating member is formed of synthetic resin filling the cavity, a core side face of a slot portion of the insulating member has both side faces and a bottom face formed in a generally flat shape, a coil side face of the slot portion of the insulating member has both side faces and bottom face formed in a generally flat shape, and the slot portion has a thick portion in at least one portion that is thicker than other portions.
 12. The method of manufacturing the core provided with the insulating member according to claim 11, characterized in that a cavity is formed, using the core as the die, between the core and a die having a recessed portion in which a portion corresponding to a ridge between a tooth and a core end face is wide, a thick portion is formed on a core end face portion corresponding to the recessed portion by pouring the liquefied insulating resin material in the cavity, and the thick portion is heated and pressed such that the ridge portion forms a corner portion of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center.
 13. The method of manufacturing the core provided with the insulating member according to claim 11, characterized in that a cavity is formed, using the core as the die, between the core and a die opposing a core end face, by a ridge portion between a tooth and the core end face, the cavity corresponding to a corner portion of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center, and the corner portion is molded by pouring the liquefied insulating resin material in the cavity.
 14. The method of manufacturing the core provided with the insulating member according to claim 11, characterized in that a first cavity is formed, using the core as the die, between the core and a die opposing one core end face, the first cavity having a recessed portion in which a portion corresponding to a ridge between a tooth and the core end face is wide, a second cavity is formed, by the ridge portion between the tooth and the core end face, between the core and a die opposing the other core end face, the second cavity corresponding to a corner portion of a chamfer shape or a rounded shape having a curvature radius larger than a radius with the ridge portion as a center, a thick portion is formed on a core end face portion corresponding to the recessed portion by pouring the liquefied insulating resin material in the first cavity, the thick portion is heated and pressed to mold the corner portion on the one core end face, and the corner portion on the other core end face is molded by pouring the liquefied insulating resin material in the secured cavity. 